Fluid-actuated cylinder assemblage

ABSTRACT

A fluid-actuated cylinder assemblage of a type which can be readily serviced or repaired, even in the field. A cylinder has an end cap and a piston and rod are slidable within the cylinder. The piston and rod can be threaded into assembly, and the rod is hollow so that a work tool can extend into the rod and engage the piston for controlling the piston in the screwing action between the rod and the piston for assembly and disassembly thereof. A fluid seal and a rod wiper exist between the cylinder and the rod and the seal is spaced inwardly from the end of the cylinder but is accessible for replacement when the rod is unscrewed relative to the piston and is removed from the cylinder. Also, the end cap and a fluid port and the piston itself are all arranged so that fluid can enter the cylinder to provide a working force on the piston, even when the piston is in its end limit position abutting a wall or face presented on the end cap.

United States Patent [191 Kulhavy arch 20, 1973 FLUID-ACTUATED CYLINDERPrimary Examiner-Paul E. Maslousky ASSEMBLAGE Attorney-Arthur J.Hansmann 75 In nt o hT.K lha D rt,l

[ ve or J sep u vy, avenpo owa ABSTRACT [73] Assignee: J. I. CaseCompany, Racine, Wis.

A fluid-actuated cylmder assemblage of a type which [22] Filed: Jan. 10,1972 Appl. No.: 216,634

can be readily serviced or repaired, even in the field. A cylinder hasan end cap and a piston and rod are slidable within the cylinder. Thepiston and rod can be threaded into assembly, and the rod is hollow sothat a work tool can extend into the rod and engage the piston forcontrolling the piston in the screwing action between the rod and thepiston for assembly and disassembly thereof. A fluid seal and a rodwiper exist between the cylinder and the rod and the seal is spacedinwardly from the end of the cylinder but is accessible for replacementwhen the rod is unscrewed relative to the piston and is removed from thecylinder. Also, the end cap and a fluid port and the piston itself areall arranged so that fluid can enter the cylinder to provide a workingforce on the piston, even when the piston is in its end limit positionabutting a wall or face presented on the end cap.

7 Claims, 3 Drawing Figures duty service but which is readilyservicable, even in the field.

BACKGROUND OF THE INVENTION Fluid-actuated cylinder assemblages arewell-known in many different forms. These cylinders may be powered bypneumatic pressure or hydraulic pressure, and they may be a single ordouble-acting type units. The design of these units is concerned withproviding a fluid-tight, sturdy, efficient, and compact and easy-actingunits. Of further concern in the design of these units, and ofparticular concern in the design of the unit disclosed herein, is theproblem of assembling and servicing the units which are fluid-tightlysealed for efficient operation. For the most part, these units must bemanufactured in a complex and intricate manner for both the purpose oforiginal assembly, particularly relative to the assembly of the pistonwith the piston rod, and they must also be manufactured for the purposeof easy servicing. Examples of certain prior art patents are found inU.S. Pat. Nos. 2,987,046 and 3,065,734 and 3,486,419. These prior artexamples do not fully concern themselves with the problems involved inthe present invention, and they also do not suggest any teachings whichwould result in solutions to the problems of concern herein.

Accordingly, it is a primary object of this invention to provide afluid-actuated cylinder assemblage which can be readily and easilymanufactured and assembled, and which can be readily and easilyserviced, even in the field.

Still further, it is an object of the present invention to provide afluid-actuated cylinder assemblage which has the aforementionedattributes and which can be made in a compact and virtually minimumsize. These objectives are accomplished with a minimum of parts and witha simplicity of structure, and this also lends to the feature ofservicing in the field.

Still another object is to provide the assemblage of the naturementioned, and to have it achieve the aforementioned objectives, and todo so with a unit which, while it is compact and sturdy and of a minimumnumber of parts, it is also arranged so that it will always respond tothe introduction of fluid pressure into the cylinder. That is, the unitwill not block or otherwise obstruct the action of the working fluid,even when the piston is in the'inward end of its stroke and even thoughthe unit may be a single-acting type.

Still further, it is an object of this invention to provide afluid-actuated cylinder assemblage which can be readily assembled anddisassembled, both in the manufacture of the assemblage and in theservice thereof, but the unit does not damage itself by scoring in theaction between the parts thereof, and it does not unduly force upon theparts relative to each other. In this particular regard, this inventionis an improvement upon units of the type shown in U.S. Pat. No.3,486,4l9, though that unit is one which lends itself to servicing inthe field, though it is ofa somewhat different structure from thatdescribed herein.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view, partly insection, of one embodiment of this invention.

FIG. 2 is a side view, partly in secton, of another embodiment of thepiston which may be utilized in FIG. 1.

FIG. 3 is an end elevational view of FIG. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows theassemblage or unit which generally consists of a cylinder 10, a piston11, and a piston rod 12. The cylinder 10 is in two cylindrical pieces 13and 14 which are secured together by means of a weldment 16. Thecylinder piece 13 has a large interior wall 17, and the piece 14 has asmaller interior wall 18, so the pieces 13 and 14 are of differentinterior diametrical sizes. Thus the cylindrical wall 18 forms thebearing for the cylindrical rod 12, as shown. Further, the piston 11includes an enlarged end 19 which is circular and discshaped and whichis of the circular size of the larger circular interior 17 and which issnugly slidably disposed within the piece 13.

The rod 12 has a hollow interior 21 for the entire length of the rod 12,and the piston 11 has a plug end 22 which is smaller in diameter thanthe diameter of the piston head or portion 19. Thus the end 22telescopes within the end 23 of the rod 12. The rod end 23 has threads24 on the interior thereof, and the piston has threads 26 engaged withthe threads 24 for the as sembly of the piston 11 with the rod 12. Agasket 27 may be disposed between the rod 12 and the piston head 19 forfurther fluid-tightly sealing, that is beyond the fluid tightnessprovided by the threads 24 and 26, between the piston 11 and rod 12.

At this time it will also be noted that the piston head or portion 19presents a ring-shaped wall 28 which abuts the ring-shaped wall 29 ofthe cylinder piece 14 when the piston and rod assembly are moved totheir extreme right-hand direction shown in FIG. 1. With thisarrangement, the wall 29 provides a firm stop for the piston and rodassembly, and there is no damage to the parts. Further, the piston 19 isof a smooth circular exterior shape and it therefore smoothly slides inthe cylinder interior 17 and does not score or otherwise damage theparts.

A cap 29 is secured to one end of the cylinder 10 by means of a weldment31, and the cap 29 has a reduced circular portion 32 telescoped withinthe cylinder 10. Further, the cap 29 has a conically-shaped end 33 whichterminates in an end wall 34 which is shown to be in abutment with thepiston face 36 when the piston 11 is in the extreme leftward position asshown in FIG. 1. The cylinder 10 also has a port 37 for the passage offluid, either pneumatic or hydraulic, relative to the interior of thecylinder 10. A threaded fitting or connector 38 is shown secured to thecylinder 10 by the weldment 39 for conducting the fluid flow relative tothe port 37.

It will therefore be seen and understood that the cap 29 and the piston11 and the port 37 are all arranged so that a space 41 is provided inthe cylinder 10 even when the piston 11 is in its lefthand end limitposition shown in FIG. 1. Therefore, working fluid can always beintroduced into the cylinder 10 and it will be applied against thepiston face 36 to activate the piston.

In connection with the aforementioned, it will be seen and understoodthat the assemblage shown is of a single acting type of cylinder. Inthis context, it should also be appreciated that the lefthand end of thecylinder 10, as just described, is of optimum compactness but yetassures fully satisfactory and efficient operation of the assemblage.That is, the cap inner portions 32 and 33 serve the respective functionsof mating with the cylinder and providing a stop for the piston 11 andalso for providing the fluid inlet space 41.

The cap 29 has an opening 42, and the rod 12 has an opening 43, and theopenings 42 and 43 are available for mounting the assemblage between twopoints, such as mounting pins which are not shown but which are commonlyused in the mounting of power cylinders.

The cylinder wall 18 has a ring-shaped fluid seal 44 disposed within agroove 46 in the wall 18. The seal 44 thus prevents the escape of fluidfrom the interior of the cylinder 10 and along the circular exterior ofthe rod 12, since the seal 44 is interposed between the cylinder 10 andthe rod 12, as shown. Also, a ringshaped wiper 47 is disposed at the endwall 48 of the cylinder 10 and is in contact with the exteriorcircularsurface 49 of the rod 12. Thus the seal 44 and the wiper 47 serve theirstandard functions of fluid sealing and dirt wiping along the rodexterior 49.

The piston 11 and rod 12 are threaded together, as described and shown,and it will be noted that the piston 11 is shown to have the boss orreduced portion 22 broken away to show the interior thereof. Thesepieces 11 and 12 are screwed together while they are within the cylinder10, and the piston 11 is held against rotation, or conversely isrotated, by means of a tool, such as a spanner wrench, which can reachinto the hollow rod 12 and which has two teeth for being received by andthus engaging the two openings 51 in the piston 11. It will therefore beunderstood that the assemblage can be created by positioning the piston11 within the cylinder 10 and then securing the cap 29 on the cylinder10, and this could actually be by threading the cap 29 into the cylinder10. The rod 12 can be inserted into the cylinder 10, and the piston 11and rod 12 can then be screwed together, by virtue of the spanner wrenchor like tool and by virtue of the hollow rod 12 and formation of thepiston 11 with the tooling portions 51.

An important feature is that by use of the spanner wrench or like tool,the piston 11 and rod 12 can be disassembled, and the seal 44 can thenbe serviced or replaced This servicing can be done in the field, and noother part of the assemblage need be taken off or apart. Also, the wiper47 could also likewise be replaced, and even the rod 12 could beserviced or replaced, all by virtue of the disassembly featuredescribed. The tool or spanner wrench is not shown, and it need not beshown since it is of a obvious or conventional design and is readilyunderstood by one skilled in the art.

H6. 3 shows a modified configuration of the toolreceiving portion of thepiston which is designated 52 in FIGS. 2 and 3. Thus the piston boss orinner portion 22 is shown to have a hexagonally-shaped opening 53axially disposed in the piston 52 and in lieu of the spaced-apartopenings 51 in the piston 11. Thus, in the embodiment shown in FIGS. 2and 3, it will be readily understood that the inner end of the too]would be hexagonally shaped in a stud which is snugly received in thehexagonal opening 53 to thus control the piston 52 in the screwingassembly and disassembly of the piston 52 and the rod 11.

In making these field repairs as described, one need not go through theport opening 37 for disconnecting the piston 11 from the rod 12. Thatis, in the prior arrangements where access is made through the port 37,this entails the disconnection of the fluid line with the fitting 38,and this in turn would involve the exposure of fluid pressure to theatmosphere and would open the system to where it is subjected to air anddirt and to other hazards.

Also, by virtue of the end cap large flat wall 34, along with the snugfit of the piston circular wall 19 in the cylinder 10, the piston 11 canbe squarely and firmly controlled for the screwing action described,though no intricate or difficult maneuvering is required in order tomate the piston 11 and rod 12. Further, in the action of the assemblageitself and in achieving the leftward position shown in FIG. 1, thepiston 11 can safely abut the end cap wall 34 without any damage to theparts, and this is in distinction to the U.S. Pat. No. 2,987,046 wherethe left-end limit of the assemblage is obviously subjecting the pistonand end cap mating surfaces to damage. Still further, in that type ofprior art unit, the entire end of the cylinder is bulky and complex inmanufacture, as shown and as compared to the unit described herein.

What is claimed is:

1. In a fluid-actuated cylinder assemblage a cylinder having a fluidport, a cap on one end of said cylinder, a piston slidably disposed insaid cylinder, a piston rod threaded to said piston and being slidablein said cylinder for reciprocation of said piston and said rod in saidcylinder, a fluid seal interposed between said cylinder and said rod,the improvement comprising said rod being cylindrical and having ahollow interior for the entire length of said rod and with said pistonbeing threaded into one end of said hollow rod to fluid-tightly closesaid rod end, and said piston having a tool-engagable portion contiguousto said hollow interior of said rod and being disposed to be accessibleto a tool through the other end of said rod for the control of saidpiston in the relative rotation of said piston and said rod in screwingthe latter two in assembly and disassembly of the assemblage.

2. The assemblage as claimed in claim 1, wherein said cap has a wallfaced toward said piston and abuttable with one face of said piston forlimiting the axial movement of said piston toward said one end of saidcylinder during said assembly and disassembly and during the operationof said assemblage, and said port being located and said cap and saidpiston, in the position of said limit of axial movement of said pistonbeing disposed and shaped to define a space in said cylinder all for theentry of fluid into said cylinder through said port and against said oneface of said piston.

3. The assemblage as claimed in claim 2, wherein one end of said capincludes a cylindrical portion telescopically extending into saidcylinder and being fluid tight with said cylinder, said cap one endterminating in a reduced portion between said cylindrical portion andsaid wall to spaced from the interior wall of said cylinder for definingsaid space.

4. The assemblage as claimed in claim 1, wherein said tool-engagableportion is an opening in said piston and is faced toward said other endof said rod for receiving the tool.

5. The assemblage as claimed in claim 1, wherein said cylinder includestwo pieces of different internal diameters, said piston being of acircular shape of the size of the larger of said cylinder diameters andbeing snugly slidably disposed in said larger diameter piece, saidsmaller diameter piece having an end extending into said larger diameterpiece and presenting an abutment for limiting the movement of saidpiston in the axial direction away from said cap.

6. The assemblage as claimed in claim 5, wherein said rod is of an outerdiameter of the size of said smaller diameter and is snugly slidablytelescoped with said smaller diameter, and said seal is disposed spacedinwardly from the outer end limit of said smaller diameter piece and isaccessible for replacement only when said piston and said rod areunscrewed and said rod is removed from said cylinder.

7. The assemblage as claimed in claim 1, wherein said seal is disposedadjacent the end of said cylinder opposite the location of said cap andspaced from the latter said cylinder end and is accessible'forreplacement only when said piston and said rod are unscrewed and saidrod is removed from said cylinder.

1. In a fluid-actuated cylinder assemblage a cylinder having a fluidport, a cap on one end of said cylinder, a piston slidably disposed insaid cylinder, a piston rod threaded to said piston and being slidablein said cylinder for reciprocation of said piston and said rod in saidcylinder, a fluid seal interposed between said cylinder and said rod,the improvement comprising said rod being cylindrical and having ahollow interior for the entire length of said rod and with said pistonbeing threaded into one end of said hollow rod to fluid-tightly closesaid rod end, and said piston having a tool-engagable portion contiguousto said hollow interior of said rod and being disposed to be accessibleto a tool through the other end of said rod for the control of saidpiston in the relative rotation of said piston and said rod in screwingthe latter two in assembly and disassembly of the assemblage.
 2. Theassemblage as claimed in claim 1, wherein said cap has a wall facedtoward said piston and abuttable with one face of said piston forlimiting the axial movement of said piston toward said one end of saidcylinder during said assembly and disassembly and during the operationof said assemblage, and said port being located and said cap and saidpiston, in the position of said limit of axial movement of said pistonbeing disposed and shaped to define a space in said cylinder all for theentry of fluid into said cylinder through said port and against said oneface of said piston.
 3. The assemblage as claimed in claim 2, whereinone end of said cap includes a cylindrical portion telescopicallyextending into said cylinder and being fluid tight with said cylinder,said cap one end terminating in a reduced portion between saidcylindrical portion and said wall to spaced from the interior wall ofsaid cylinder for defining said space.
 4. The assemblage as claimed inclaim 1, wherein said tool-engagable portion is an opening in saidpiston and is faced toward said other end of said rod for receiving thetool.
 5. The assemblage as claimed in claim 1, wherein said cylinderincludes two pieces of different internal diameters, said piston beingof a circular shape of the size of the larger of said cylinder diametersand being snugly slidably disposed in said larger diameter piece, saidsmaller diameter piece having an end extending into said larger diameterpiece and presenting an abutment for limiting the movement of saidpiston in the axial direction away from said cap.
 6. The assemblage asclaimed in claim 5, wherein said rod is of an outer diameter of the sizeof said smaller diameter and is snugly slidably telescoped with saidsmaller diameter, and said seal is disposed spaced inwardly from theouter end limit of said smaller diameter piece and is accessible forreplacement only when said piston and said rod are unscrewed and saidrod is removed from said cylinder.
 7. The assemblage as claimed in claim1, wherein said seal is disposed adjacent thE end of said cylinderopposite the location of said cap and spaced from the latter saidcylinder end and is accessible for replacement only when said piston andsaid rod are unscrewed and said rod is removed from said cylinder.